[Asterisk-Users] 1.2.0 PRI dropping calls occasionally...

[Steve Davies]

On 12/1/05, Rob Thomas <rob at wpm4l.com> wrote:
> After upgrading to 1.2.0 (from a three-week-prior CVS version), I've
> suddenly had people starting to complain of lost calls. They'd be there,
> and suddenly they'd drop out - they could be in a conversation, or more
> often, the caller would be on old, and suddenly the light would go out,
> and the caller would be gone.
>
> I haven't noticed anything unusual in the logs, nothing that stands out
> anyway. Is anyone else experiencing anything like this?

This is probably completely unrelated, particularly as it occurs on a
1.0.9 system, but we have one box which occasionally reports a PRI
"D-Channel up" message, resulting in killed calls, even though the
D-Channel is already up and working.

In our case it was fax-tone detection (for echo canceller switch-off)
in zaptel which seems to cause it. We have compiled this feature out
on this one server as a workaround. This can be spotted by looking for
the zaptel message in dmesg showing tone detection.

Strangely, the EXACT same software build and O/S with the same PRI
hardware and driver does not cause this problem on any of our other
servers.

Regards,
Steve